A key challenge to forming a conventional partial FOX FinFET structure is that epitaxial crystal growth in source/drain involves vertical (i.e., bottom-up) epitaxial crystal growth from a silicon substrate and lateral epitaxial crystal growth from sidewalls of a silicon fin. The multi-dimensional source/drain epitaxy resulting from the vertical and lateral epitaxial crystal growths may include, thereby degrading device performance. Therefore, there is a need for forming a partial FOX FinFET having a dielectric only under a fin channel.